The invention starts from a backflush filter in accordance with DE 32 35 552 C2, which is incorporated by reference into the specification of this application along with any English translations thereof. The citation mentioned already describes the fundamental construction of a backflush filter having a filter insert that has a supporting cage with apertures which are arranged in groups that are offset relative to one another. DE 32 35 552 C2 describes a first embodiment, in which all the rectangular apertures extend with their longer side in the circumferential direction of the filter insert or in a plane perpendicular to the filter insert axis and in which the backflushing device is designed as a cylindrical flushing plate which can be moved up and down within the filter insert by means of a connecting rod. In a second embodiment, the individual apertures are aligned axially, i.e. the longitudinal side of the rectangular apertures extends parallel to the longitudinal axis of the filter insert, and the flushing device consists of a rotatable flushing arm. In order to clean the filtering means behind the various aperture groups by a reverse flow in the case of the last-mentioned embodiment with axially aligned apertures, the flushing arm has a plurality of slits, to each of which a separate shut-off valve is assigned, wherein the shut-off valves are controlled alternately so that in each case one of the flushing ducts is shut off from the flushing connection.